1. Field of the Invention
The invention relates to a method of synthesizing metal doped diamond-like carbon films.
2. Description of the Prior Art
Metal doped diamond-like carbons films are useful as wear and corrosion resistant coatings for a wide array of devices, ranging from electrodes for electrochemistry to protection of critical components used in space shuttles. A recent development useful in the medical sciences is the use of precious metal substrates in diagnostic strips in order to isolate the reactants from contamination and improve accuracy of the test.
Current methods use co-sputtering of metal during amorphous carbon film deposition in RF plasma reactor or in a complete PVD setup to synthesize metal doped diamond-like carbon films. These methods, however, do not provide control for film composition.
The need remains to provide a method that allows independent process control of film composition to provide flexibility and/or structure modification.
The present invention is a new method for synthesizing metal-doped amorphous (diamond-like) carbon films using plasma assisted decomposition of metalorganic precursors. The invention sets forth a process of synthesizing metal doped carbon films by placing a substrate in a chamber with a selected amount of a selected metalorganic compound. An electron cyclotron resonance is applied to the chamber in order to vaporize the metalorganic compound and continued resonance may be applied to the chamber until a metal doped carbon film is formed.
More particularly, a metalorganic precursor for the desired diamond-like carbon film is treated by a electron cyclotron resonance (ECR) chemical vapor deposition (CVD) technique to form a film on a substrate. The metalorganic compound is preferably selected from the group consisting of a metal of an organic salt of ruthenium, palladium, gold or platinum. Preferred substrates are silicon and quartz. The organic moiety can be any organic compound.
A most preferred metalorganic precursor is bis-(ethylcyclopentany) ruthenium. The substrate is biased using an RF power source between xe2x88x9230 and xe2x88x92100V with respect to system ground, i.e., chamber. The flow rates were set below 5 sccm.
It is an object of the present invention to synthesize novel material systems possessing unique combination of properties including conducting and hard films, semi-conducting films, and catalytic and electrocatalytic materials.
It is an object of the present invention to improve the properties of diamond-like carbon films such as stability, wear resistance in vacuum environments and adhesion with substrates.
It is an object of the present invention to utilize metalorganic chemical vapor deposition, (MOCVD), precursor decomposition for metal doping as opposed to conventional co-sputtering methods for metal doping.
It is an object of the present invention to provide for independent controllable synthesis variables such as substrate bias, power and gas phase composition for dopant.
It is an object of the present invention to reduce contamination because no electrodes are used and the ability to use high purity source materials.
It is an object of the present invention to eliminate line of sight problems for deposition over complex geometries.
It is an object of the present invention to provide ultra thin and wear resistant coatings for scanning tunnel microscope, (SPM), probe tips.
It is an object of the present invention to provide for conduction versions for S-parameter microscopy, (SPM), specifically.
It is yet another object of the present invention to provide a means for control for film composition.
It is another object of the present invention to obtain precursor materials at a very high purity compared to sputtering targets.
These and other objects of the present invention will be more fully understood from the following description of the invention.